Families of the 20 students and six staff members killed in the Sandy Hook Elementary School shooting have filed a lawsuit against the town of Newtown, Connecticut, and the school board, alleging that lax security contributed to the massacre, according to the Hartford Courant. It’s the second lawsuit filed since the December 2012 shooting -- the first one was brought by 10 families against the gun manufacturer of the Bushmaster AR-15, a military assault weapon used by the lone gunman.

The families in the newest lawsuit may see relief long before the families suing the gun maker do, as a law enacted by Congress and signed by President George W. Bush in 2005, the Protection of Lawful Commerce in Arms Act, provides some immunity to gun manufacturers and dealers from civil lawsuits for the crimes committed with the products they sell. City governments and school districts have no such protections.

The new 66-page lawsuit, which is seeking more than $15,000 in damages, was filed around Dec. 14, on the last day a state statute of limitations would allow legal action to be taken. An attorney representing the families said in a statement Monday that their sole motivation was to improve school security for current and future students in the Newtown school district.

"We are hopeful that the Town of Newtown's elected and hired representatives will work with these families, who have already suffered, and continue to suffer, unimaginable loss, to help resolve this matter in the most efficient and constructive way possible," Donald Papcsy, the attorney representing the estates of slain students Noah Pozner and Jesse Lewis, said. "As residents of the town, we all either have, or are going to have, students in our Sandy Hook schools, and we promote the idea of learning from the past and protecting our children in the future."

The lawsuit describes what the plaintiffs perceive as security lapses and specifically alleges that a substitute teacher had no “knowledge of the … safety procedures and security protocols rehearsed at the Sandy Hook Elementary School in case an intruder or other dangerous individual gained access to the school.” On Dec. 14, 2012, Adam Lanza entered the school through doors near the school's main offices and, after killing the principal and school psychologist, entered two classrooms full of students, one of which the substitute teacher was unable to lock because she didn’t have a key.

The lawsuit also charges the town with negligence in not having bulletproof glass on the school’s front windows, in having doors that can't be locked from the inside, and in a lack of parking lot security, as Lanza parked his car less than 100 feet from the school entrance.